linux/drivers/mmc/host/dw_mmc-rockchip.c
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   1/*
   2 * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/platform_device.h>
  12#include <linux/clk.h>
  13#include <linux/mmc/host.h>
  14#include <linux/mmc/dw_mmc.h>
  15#include <linux/of_address.h>
  16#include <linux/mmc/slot-gpio.h>
  17#include <linux/pm_runtime.h>
  18#include <linux/slab.h>
  19
  20#include "dw_mmc.h"
  21#include "dw_mmc-pltfm.h"
  22
  23#define RK3288_CLKGEN_DIV       2
  24
  25struct dw_mci_rockchip_priv_data {
  26        struct clk              *drv_clk;
  27        struct clk              *sample_clk;
  28        int                     default_sample_phase;
  29};
  30
  31static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  32{
  33        struct dw_mci_rockchip_priv_data *priv = host->priv;
  34        int ret;
  35        unsigned int cclkin;
  36        u32 bus_hz;
  37
  38        if (ios->clock == 0)
  39                return;
  40
  41        /*
  42         * cclkin: source clock of mmc controller
  43         * bus_hz: card interface clock generated by CLKGEN
  44         * bus_hz = cclkin / RK3288_CLKGEN_DIV
  45         * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
  46         *
  47         * Note: div can only be 0 or 1
  48         *       if DDR50 8bit mode(only emmc work in 8bit mode),
  49         *       div must be set 1
  50         */
  51        if (ios->bus_width == MMC_BUS_WIDTH_8 &&
  52            ios->timing == MMC_TIMING_MMC_DDR52)
  53                cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
  54        else
  55                cclkin = ios->clock * RK3288_CLKGEN_DIV;
  56
  57        ret = clk_set_rate(host->ciu_clk, cclkin);
  58        if (ret)
  59                dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
  60
  61        bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
  62        if (bus_hz != host->bus_hz) {
  63                host->bus_hz = bus_hz;
  64                /* force dw_mci_setup_bus() */
  65                host->current_speed = 0;
  66        }
  67
  68        /* Make sure we use phases which we can enumerate with */
  69        if (!IS_ERR(priv->sample_clk))
  70                clk_set_phase(priv->sample_clk, priv->default_sample_phase);
  71
  72        /*
  73         * Set the drive phase offset based on speed mode to achieve hold times.
  74         *
  75         * NOTE: this is _not_ a value that is dynamically tuned and is also
  76         * _not_ a value that will vary from board to board.  It is a value
  77         * that could vary between different SoC models if they had massively
  78         * different output clock delays inside their dw_mmc IP block (delay_o),
  79         * but since it's OK to overshoot a little we don't need to do complex
  80         * calculations and can pick values that will just work for everyone.
  81         *
  82         * When picking values we'll stick with picking 0/90/180/270 since
  83         * those can be made very accurately on all known Rockchip SoCs.
  84         *
  85         * Note that these values match values from the DesignWare Databook
  86         * tables for the most part except for SDR12 and "ID mode".  For those
  87         * two modes the databook calculations assume a clock in of 50MHz.  As
  88         * seen above, we always use a clock in rate that is exactly the
  89         * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided
  90         * back out before the controller sees it).
  91         *
  92         * From measurement of a single device, it appears that delay_o is
  93         * about .5 ns.  Since we try to leave a bit of margin, it's expected
  94         * that numbers here will be fine even with much larger delay_o
  95         * (the 1.4 ns assumed by the DesignWare Databook would result in the
  96         * same results, for instance).
  97         */
  98        if (!IS_ERR(priv->drv_clk)) {
  99                int phase;
 100
 101                /*
 102                 * In almost all cases a 90 degree phase offset will provide
 103                 * sufficient hold times across all valid input clock rates
 104                 * assuming delay_o is not absurd for a given SoC.  We'll use
 105                 * that as a default.
 106                 */
 107                phase = 90;
 108
 109                switch (ios->timing) {
 110                case MMC_TIMING_MMC_DDR52:
 111                        /*
 112                         * Since clock in rate with MMC_DDR52 is doubled when
 113                         * bus width is 8 we need to double the phase offset
 114                         * to get the same timings.
 115                         */
 116                        if (ios->bus_width == MMC_BUS_WIDTH_8)
 117                                phase = 180;
 118                        break;
 119                case MMC_TIMING_UHS_SDR104:
 120                case MMC_TIMING_MMC_HS200:
 121                        /*
 122                         * In the case of 150 MHz clock (typical max for
 123                         * Rockchip SoCs), 90 degree offset will add a delay
 124                         * of 1.67 ns.  That will meet min hold time of .8 ns
 125                         * as long as clock output delay is < .87 ns.  On
 126                         * SoCs measured this seems to be OK, but it doesn't
 127                         * hurt to give margin here, so we use 180.
 128                         */
 129                        phase = 180;
 130                        break;
 131                }
 132
 133                clk_set_phase(priv->drv_clk, phase);
 134        }
 135}
 136
 137#define NUM_PHASES                      360
 138#define TUNING_ITERATION_TO_PHASE(i)    (DIV_ROUND_UP((i) * 360, NUM_PHASES))
 139
 140static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 141{
 142        struct dw_mci *host = slot->host;
 143        struct dw_mci_rockchip_priv_data *priv = host->priv;
 144        struct mmc_host *mmc = slot->mmc;
 145        int ret = 0;
 146        int i;
 147        bool v, prev_v = 0, first_v;
 148        struct range_t {
 149                int start;
 150                int end; /* inclusive */
 151        };
 152        struct range_t *ranges;
 153        unsigned int range_count = 0;
 154        int longest_range_len = -1;
 155        int longest_range = -1;
 156        int middle_phase;
 157
 158        if (IS_ERR(priv->sample_clk)) {
 159                dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n");
 160                return -EIO;
 161        }
 162
 163        ranges = kmalloc_array(NUM_PHASES / 2 + 1, sizeof(*ranges), GFP_KERNEL);
 164        if (!ranges)
 165                return -ENOMEM;
 166
 167        /* Try each phase and extract good ranges */
 168        for (i = 0; i < NUM_PHASES; ) {
 169                clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i));
 170
 171                v = !mmc_send_tuning(mmc, opcode, NULL);
 172
 173                if (i == 0)
 174                        first_v = v;
 175
 176                if ((!prev_v) && v) {
 177                        range_count++;
 178                        ranges[range_count-1].start = i;
 179                }
 180                if (v) {
 181                        ranges[range_count-1].end = i;
 182                        i++;
 183                } else if (i == NUM_PHASES - 1) {
 184                        /* No extra skipping rules if we're at the end */
 185                        i++;
 186                } else {
 187                        /*
 188                         * No need to check too close to an invalid
 189                         * one since testing bad phases is slow.  Skip
 190                         * 20 degrees.
 191                         */
 192                        i += DIV_ROUND_UP(20 * NUM_PHASES, 360);
 193
 194                        /* Always test the last one */
 195                        if (i >= NUM_PHASES)
 196                                i = NUM_PHASES - 1;
 197                }
 198
 199                prev_v = v;
 200        }
 201
 202        if (range_count == 0) {
 203                dev_warn(host->dev, "All phases bad!");
 204                ret = -EIO;
 205                goto free;
 206        }
 207
 208        /* wrap around case, merge the end points */
 209        if ((range_count > 1) && first_v && v) {
 210                ranges[0].start = ranges[range_count-1].start;
 211                range_count--;
 212        }
 213
 214        if (ranges[0].start == 0 && ranges[0].end == NUM_PHASES - 1) {
 215                clk_set_phase(priv->sample_clk, priv->default_sample_phase);
 216                dev_info(host->dev, "All phases work, using default phase %d.",
 217                         priv->default_sample_phase);
 218                goto free;
 219        }
 220
 221        /* Find the longest range */
 222        for (i = 0; i < range_count; i++) {
 223                int len = (ranges[i].end - ranges[i].start + 1);
 224
 225                if (len < 0)
 226                        len += NUM_PHASES;
 227
 228                if (longest_range_len < len) {
 229                        longest_range_len = len;
 230                        longest_range = i;
 231                }
 232
 233                dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n",
 234                        TUNING_ITERATION_TO_PHASE(ranges[i].start),
 235                        TUNING_ITERATION_TO_PHASE(ranges[i].end),
 236                        len
 237                );
 238        }
 239
 240        dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n",
 241                TUNING_ITERATION_TO_PHASE(ranges[longest_range].start),
 242                TUNING_ITERATION_TO_PHASE(ranges[longest_range].end),
 243                longest_range_len
 244        );
 245
 246        middle_phase = ranges[longest_range].start + longest_range_len / 2;
 247        middle_phase %= NUM_PHASES;
 248        dev_info(host->dev, "Successfully tuned phase to %d\n",
 249                 TUNING_ITERATION_TO_PHASE(middle_phase));
 250
 251        clk_set_phase(priv->sample_clk,
 252                      TUNING_ITERATION_TO_PHASE(middle_phase));
 253
 254free:
 255        kfree(ranges);
 256        return ret;
 257}
 258
 259static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
 260{
 261        struct device_node *np = host->dev->of_node;
 262        struct dw_mci_rockchip_priv_data *priv;
 263
 264        priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 265        if (!priv)
 266                return -ENOMEM;
 267
 268        if (of_property_read_u32(np, "rockchip,default-sample-phase",
 269                                        &priv->default_sample_phase))
 270                priv->default_sample_phase = 0;
 271
 272        priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
 273        if (IS_ERR(priv->drv_clk))
 274                dev_dbg(host->dev, "ciu_drv not available\n");
 275
 276        priv->sample_clk = devm_clk_get(host->dev, "ciu-sample");
 277        if (IS_ERR(priv->sample_clk))
 278                dev_dbg(host->dev, "ciu_sample not available\n");
 279
 280        host->priv = priv;
 281
 282        return 0;
 283}
 284
 285static int dw_mci_rockchip_init(struct dw_mci *host)
 286{
 287        /* It is slot 8 on Rockchip SoCs */
 288        host->sdio_id0 = 8;
 289
 290        if (of_device_is_compatible(host->dev->of_node,
 291                                    "rockchip,rk3288-dw-mshc"))
 292                host->bus_hz /= RK3288_CLKGEN_DIV;
 293
 294        return 0;
 295}
 296
 297/* Common capabilities of RK3288 SoC */
 298static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
 299        MMC_CAP_CMD23,
 300        MMC_CAP_CMD23,
 301        MMC_CAP_CMD23,
 302        MMC_CAP_CMD23,
 303};
 304
 305static const struct dw_mci_drv_data rk2928_drv_data = {
 306        .init                   = dw_mci_rockchip_init,
 307};
 308
 309static const struct dw_mci_drv_data rk3288_drv_data = {
 310        .caps                   = dw_mci_rk3288_dwmmc_caps,
 311        .set_ios                = dw_mci_rk3288_set_ios,
 312        .execute_tuning         = dw_mci_rk3288_execute_tuning,
 313        .parse_dt               = dw_mci_rk3288_parse_dt,
 314        .init                   = dw_mci_rockchip_init,
 315};
 316
 317static const struct of_device_id dw_mci_rockchip_match[] = {
 318        { .compatible = "rockchip,rk2928-dw-mshc",
 319                .data = &rk2928_drv_data },
 320        { .compatible = "rockchip,rk3288-dw-mshc",
 321                .data = &rk3288_drv_data },
 322        {},
 323};
 324MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match);
 325
 326static int dw_mci_rockchip_probe(struct platform_device *pdev)
 327{
 328        const struct dw_mci_drv_data *drv_data;
 329        const struct of_device_id *match;
 330        int ret;
 331
 332        if (!pdev->dev.of_node)
 333                return -ENODEV;
 334
 335        match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node);
 336        drv_data = match->data;
 337
 338        pm_runtime_get_noresume(&pdev->dev);
 339        pm_runtime_set_active(&pdev->dev);
 340        pm_runtime_enable(&pdev->dev);
 341        pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 342        pm_runtime_use_autosuspend(&pdev->dev);
 343
 344        ret = dw_mci_pltfm_register(pdev, drv_data);
 345        if (ret) {
 346                pm_runtime_disable(&pdev->dev);
 347                pm_runtime_set_suspended(&pdev->dev);
 348                pm_runtime_put_noidle(&pdev->dev);
 349                return ret;
 350        }
 351
 352        pm_runtime_put_autosuspend(&pdev->dev);
 353
 354        return 0;
 355}
 356
 357static int dw_mci_rockchip_remove(struct platform_device *pdev)
 358{
 359        pm_runtime_get_sync(&pdev->dev);
 360        pm_runtime_disable(&pdev->dev);
 361        pm_runtime_put_noidle(&pdev->dev);
 362
 363        return dw_mci_pltfm_remove(pdev);
 364}
 365
 366static const struct dev_pm_ops dw_mci_rockchip_dev_pm_ops = {
 367        SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 368                                pm_runtime_force_resume)
 369        SET_RUNTIME_PM_OPS(dw_mci_runtime_suspend,
 370                           dw_mci_runtime_resume,
 371                           NULL)
 372};
 373
 374static struct platform_driver dw_mci_rockchip_pltfm_driver = {
 375        .probe          = dw_mci_rockchip_probe,
 376        .remove         = dw_mci_rockchip_remove,
 377        .driver         = {
 378                .name           = "dwmmc_rockchip",
 379                .of_match_table = dw_mci_rockchip_match,
 380                .pm             = &dw_mci_rockchip_dev_pm_ops,
 381        },
 382};
 383
 384module_platform_driver(dw_mci_rockchip_pltfm_driver);
 385
 386MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
 387MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension");
 388MODULE_ALIAS("platform:dwmmc_rockchip");
 389MODULE_LICENSE("GPL v2");
 390